Linear pulse motor

Abstract

A linear pulse motor which includes: a primary magnetic flux generating unit composed of a pair of cores each having a coil wound therearound and a plurality of magnetic poles provided at end portions thereof; and a scale having a row of first teeth formed therein along a direction of relative travel thereof with respect to the magnetic flux generating unit, the scale and the flux generating unit being disposed so that the scale relatively moves with respect to the primary magnetic flux generating unit by generating magnetic flux between gaps formed between the magnetic poles and the teeth facing to the magnetic poles. The magnetic flux generating unit includes a spacer through which the cores are jointed in a parallel manner. Each core has a pair of arms and a substantially U shape, the core being provided on each end of the arms thereof with the magnetic pole. The magnetic flux generating unit is disposed with respect to the scale so that the cores are placed in one of both a direction parallel to and a direction perpendicular to the row of teeth.

What is claimed: 
     
       1. In a linear pulse motor which includes: a primary magnetic flux generating unit (27, 37) composed of a pair of cores (4, 5) each having a coil (2, 3) wound therearound and a plurality of magnetic poles (4a, 4b; 5a, 5b) provided at end portions thereof; and a scale (21; 31) having a row of first teeth (21A, 21B; 31A, 31B) formed therein along a direction of relative travel thereof with respect to the magnetic flux generating unit, the scale and the flux generating unit being disposed so that the scale moves relatively with respect to the primary magnetic flux generating unit by generating magnetic flux between gaps formed between the magnetic poles (4a, 4b; 5a, 5b) and the first teeth (21A, 21B; 31A, 31B) facing to the magnetic poles, the improvement wherein; (a) the magnetic flux generating unit (27, 37) comprises a spacer (43, 90) through which the cores are jointed in a parallel manner;   (b) each core has a pair of parallel separate yokes (45, 49; 51, 53), each yoke having a magnetic pole (61, 63, 67, 71) at one end thereof, and a connecting member (55) magnetically coupled to the other end of each yoke of the core to give the core a substanially U shape, said connecting member having the coil wound therearound; and   (c) the magnetic flux generating unit is disposed so that the cores are placed in one of a direction parallel to and a direction perpendicular to the row of first teeth (21A, 21B; 31A, 31B).   
     
     
       2. A linear pulse motor as recited in claim 1, wherein each core comprises means for interengaging each yokes (45, 49; 51, 53) to the connecting member (55), the interengaging means being disposed to other end portions of the yokes thereof and opposite end portions of the corresponding connecting member. 
     
     
       3. A linear pulse motor as recited in claim 2, wherein said interengaging means comprises a recessed portion (45C, 49C, 51C) formed at the other end portion of each yoke, and the opposite end portions of the corresponding connecting member, the opposite end portions engaging with the respective recessed portions. 
     
     
       4. A linear pulse motor as recited in claim 3, wherein said spacer (43) is made of a permanent magnet. 
     
     
       5. A linear pulse motor as recited in claim 1, 2 or 3, wherein said spacer (90) is made of a non-magnetic material, wherein the cores are disposed so that yokes of one core face to respective yokes of the other core through said spacer to form two pairs of facing yokes (45, 51; 49, 53), and wherein the magnetic flux generating unit comprises a pair of platelike permanent magnets (91, 91) attached to outside faces of respective facing yoke pairs so that the permanent magnets magnetically couples the respective facing yoke pairs.